With some new product releases, you need a magnifying glass to spot the difference. But with the new SRAM RED XPLR AXS 2024, it hits you right from the dropouts. A massive direct-mount derailleur, 13 gears, new shifters – and no derailleur hanger. SRAM are going on the offensive with this new high-end gravel groupset. We put it to the test to let you know if the attack works.

SRAM RED XPLR AXS | 2,488 g (manufacturer specification) | € 4,465 (including powermeter) | Manufacturer Website

In May 2024, SRAM launched the new RED AXS groupset, and in some components the family resemblance is unmistakable. The shifters, cranks, chain and brakes are the same as those of the road groupset. For the rear derailleur, however, you’ll have to look to a different branch of the SRAM family tree – mountain bikes. So we’ll take you on a brief tour around the rugged, technical terrain of MTB tech before shifting up a gear with the 2,488 g SRAM RED XPLR AXS groupset in the Karwendel mountains.

The Eagle soars – direct mount tech has landed on gravel bikes

If you want to see eagles in the Alps, you’ll either have to look way up or way down. SRAM Eagle Transmission is the American company’s top-of-the-range MTB drivetrain, and it adorns many a knobbly rear wheel. Instead of a delicate derailleur hanger, two massive clamps grip the thru-axle, promising ultra-precise shifting, without fiddly fine-tuning. B-screw? Upper limit? Lower limit? Forget about them! This rear derailleur has no adjustment screws at all.

The prerequisite for this direct mount bliss is the Universal Derailleur Hanger (UDH). This interface, introduced by SRAM, allows the use of either a standardised UDH hanger, or SRAM’s direct mount derailleurs. While our flat-bar buddies will probably just muster a bored yawn – UDH has long been commonplace in the MTB segment – it is still new territory for us drop-bar riders. In 2023, when we wanted to fit an Eagle Transmission derailleur to a gravel bike, we had to search far and wide for a drop-bar frame with a UDH interface. A year later and everything has changed. Specialized, Canyon, ROSE… Many of the big players are now offering UDH compatible gravel frames, and we’re boldly predicting that UDH will become the new standard for gravel bikes in the coming years. Why is this important? No UDH, no SRAM RED XPLR AXS. So, let’s get off the MTB and onto the gravel.

Massive progress? The direct mount derailleur with its massive cassette makes a bold statement on the rear wheel.

Holy cow! The SRAM RED AXS XPLR derailleur

Buttercup has never seen anything like it. The direct-mount derailleur is causing a bovine traffic jam on the way to the pasture (or maybe it’s just the salt on the saddle). At first glance, the derailleur looks massive. Combined with the large cassette and the oversized pulley wheel, it looks as if there’s more weight hanging off the frame than on some bulls necks. As it happens, the derailleur weighs in at 375 grams, about 80 grams heavier than its predecessor. However, thanks to the direct-mount aluminium clamps, it makes the derailleur hanger superfluous. The battery is well protected between the clamps, and less exposed than on SRAM road derailleurs.

The look may take some getting used to, but not the functionality – the derailleur guides the chain quickly and precisely through the 13 gears.

Once mounted, and connected to a correctly trimmed chain, the SRAM RED AXS XPLR derailleur aligns automatically and promises quick and precise gear changes. There are no adjustment screws whatsoever. The distance between the cage and the cassette is determined by the length of the chain – goodbye, B-screw. The chain is guided through the long cage by a generously sized pulley wheel. A new, stronger clutch ensures effective damping and prevents the cage from bouncing too much.

Should something other than the prying eyes of a hungry cow get stuck on this electromechanical marvel, the derailleur has a few tricks up its sleeve to prevent a total loss. The jockey wheels keep spinning even if a stick wraps around the centre, as the outer edge is able to rotate around independently, and in the event of a side impact, the derailleur shifts inward to absorb the blow. If something does bend or break, you can completely disassemble the derailleur, order spare parts, and replace them yourself. We’ve often criticised expensive parts for prioritising performance over durability and repairability, but the SRAM RED XPLR AXS takes a different approach, winning some bonus points right from the get go.

Completely replaceable – the derailleur can be dismantled and individual parts replaced.
Instead of a delicate derailleur hanger, two massive clamps grip the thru-axle.
The running surface of the “Magic Pulley” jockey wheel keeps turning, even if the wheel is sabotaged with a stick.

And what about frame protection? After all, the unloved derailleur hanger is a predetermined breaking point between the derailleur and the dropout, and its job is to keep those harmful forces away from the fragile carbon. With the RED XPLR derailleur, these forces are transferred via robust clamps to the solid thru-axle, instead of directly to the frame. According to SRAM, no frame damage was reported during testing. In fact, the construction looks impressively sturdy. We’ll keep an eye on it. But for now, Buttercup can rest easy and move on.

Rock solid – the XPLR feels very robust.

13 is a lucky number – The RED XPLR AXS cassette

I’m not sure what this curious cow’s climbing ability is, but I certainly know mine – and on paper, it matches SRAM’s range perfectly. The 10-46 ratio is designed to get me up to the Karwendelhaus and send fans of 2x setups into an existential crisis. Weighing in at 288 g, this cassette is the only option available and, according to SRAM, the only one you need. The three largest sprockets are made of aluminium, while the other 10 are made of steel. 3+10? Exactly: 13 sprockets adorn the rear wheel. The gradations are particularly fine at the lower end, with 10, 11, 12, 13, 15, 17, 19, 21, 24, 28, 32, 38 and 46 teeth, allowing you to maintain a constant cadence over varying gradients. If you really hit a wall, the 46-tooth bailout gear will have your back. The spacing between the sprockets is the same as on a 12-speed cassette.

46 good reasons to head for the mountains – the new gear ratio makes the 1x setup fit for adventure.

Same sprocket spacing but one more gear? Exactly – the cassette is wider. SRAM have worked their magic to ensure that it still fits on the XDR freehub body. At the outer end, the UDH interface provides extra installation space, while at the inner end, the large 46-tooth sprocket extends beyond the freehub body, over the rear wheel. The angle of the spokes creates the necessary clearance. This way, the available space is used to the maximum. What sounds complicated also has a practical benefit: RED XPLR AXS uses the existing 12-speed chains. A 12-speed chain is essential for compatibility with other SRAM AXS 12-speed groupsets, so you can also combine the RED XPLR AXS rear derailleur and cassette with Force AXS or Rival AXS shifters and chainset. However, a UDH compatible frame is always required.

The only disadvantage of the wider cassette is that the chain runs at a steeper angle than in other 1x setups. This increases friction and therefore wear. And wear can get expensive with high-end components – especially RED XPLR AXS.

The gear range is a delicious treat for anyone travelling on steep terrain.

Chain-ging it up – The RED XPLR AXS crankset

The power transmission from the crank to the cassette is handled by the flat top chain, introduced with the RED AXS road launch. Special cut-outs shave a few grams off the weight. The cranks themselves are also from the RED AXS group. Whether you want to track your wattage with a power meter is up to you. The good news is that if you opt for the power meter, it won’t be fixed to the chainring. This means you can replace worn chainrings or try new gear ratios, without having to discard an expensive power meter every time. It may sound obvious, but at least with SRAM’s top road 2x groupsets, chainrings and power meter come as a single unit.

1x is the only option – SRAM say goodbye to the second chainring with RED XPLR AXS.

The chainrings are available in all the usual sizes: 38, 40, 42, 44 and 46 teeth. If you want to go really fast, SRAM also offer aero versions with 48, 50 and 52 teeth. Also new is the mechanism for fixing the chainrings. Rather than SRAM’s usual 8 screws, the rings are attached to the crank via a central lockring, requiring a special tool to install.

No matter how much you tinker, you won’t be able to fit more than one chainring on the crank arm. SRAM, the pioneer of 1x drivetrains, have designed their new high-end gravel groupset exclusively as a 1x setup. This is a clear challenge to Shimano, who continue to focus on 2x with their GRX Di2. On paper, SRAM’s RED XPLR AXS looks impressive in this battle of concepts. It boasts 13 gears, adventure-friendly ratios, compatibility between AXS components, and exciting new direct-mount technology. But can RED XPLR AXS live up to its theoretical promise in the real world?

Mechanics rejoice – changing the chainrings requires yet another proprietary tool!
Unlike the 2x road groupsets, the chainring and the power meter are not permanently attached to each other.

One-finger wonder – The RED XPLR AXS shifters

If the derailleur is the eye-catcher at the rear, the shifters are the revolution at the front. Borrowed from the RED AXS road group, they contain more surprises than we would have expected from a brake lever in 2024. At the heart of it all is the repositioned brake piston. This, together with the modified pivot point of the brake lever, results in a sleeker look, improved cockpit ergonomics and enhanced braking performance.

The new hoods no longer stick up awkwardly like two dip sticks in the wind (looking at you, original RED AXS). Instead, they stretch out elegantly to provide more surface area, better control and significantly improved ergonomics. The texture of the rubber grips helps with installation and alignment. On the inside of the hoods, SRAM have added a small, fully programmable thumb switch. This bonus switch can be used to control your GPS computer or shift gears. Is it just a gimmick, or a really useful feature? Well, in some test situations, this little rubber button proved to be a real game changer.

Easy to grasp: one finger is all it takes to engage the incredible braking power of the new levers.

The new carbon brake levers curve outward and, together with the longer hoods, prevent finger pinching during impulsive braking manoeuvres. And this is where things get really interesting. SRAM promise up to 80% better braking performance in the hoods with the new brakes, emphasising this claim with the lever’s design. The RED XPLR AXS is built for one-finger braking. The index finger finds a secure hold on the gently curved brake lever, the thumb rests on the extra switch, and three fingers grip the handlebar. It feels good, but is the braking power in this position really sufficient? I decided to indulge in an extra portion of traditional sugary pancakes to push my weight over the 90 kilo mark, then put the brakes to the test on the descent from the Karwendelhaus.

Overall, the hoods have become much more streamlined.
The rubber grips provide a secure hold without causing calluses.
Standstill is progress: The brake in combination with the new levers is impressive.

Breaking the bank for gravel glory – The RED XPLR AXS price tag

After adding up the individual prices of the components, including the power meter, I landed at € 2,865. And then I realised I had forgotten to include the shifters, brakes and chain. Ouch. € 1,600 later, I arrive at a whopping € 4,465. The price of the cassette, in particular, brings on the very sweat it’s supposed to prevent with its fabulous gear range: € 675 for a wear part that’s going to take a beating in gravel use? Your heart rate and blood pressure will be sky high before you even reach the foot of your first climb. The good news is that if you buy the RED XPLR AXS as a complete groupset, you’ll find much better deals. Or you can opt for a less prestigious component mix, opting for just the rear derailleur and cassette, combining it with your existing AXS 12-speed groupset.

First test – How the RED XPLR AXS performs

The SRAM marketing team must have had a good laugh sending us up the 4 km, 10% gravel climb to Hochalmkreuz in 31 degree heat. This is exactly where the 46 tooth sprocket makes perfect sense, or at the end of a long bikepacking day, or on slippery surfaces, or for gravel beginners, or, or, or…

Where other race-oriented 1x setups can leave you desperately mashing the shifter and hoping that the biggest sprocket has miraculously grown a few extra teeth in the last three seconds, RED XPLR AXS delivers a smooth, fast and reliable shift. The 13th gear isn’t just a lifesaver in high alpine terrain, it also allows for fine gradation throughout the gear range. Big gear jumps become small “gear hops”, ensuring a smooth, efficient pedal stroke and consistent cadence.

This is where the RED XPLR AXS differs from the mullet setup with its massive 10-52 spread. With this adventure setup, the gear jumps, especially in the lower range, are much bigger. That’s perfectly fine for bikepackers and world tourers, but those looking for speed will appreciate the smaller jumps between gears with RED XPLR AXS.

While the visual resemblance to Transmission is undeniable, RED XPLR AXS is different in one key way: it’s faster. Whereas the Eagle Transmission relies on specific shift paths to decide when the chain moves from one sprocket to the next, RED XPLR AXS does it instantly. This gravel groupset is designed for maximum speed rather than smooth shifts under full load. However, we didn’t notice any loss in shifting smoothness. On the contrary, kudos to the confidence of the direct-mount derailleur in changing gears under load.

With another helping of pancakes in my belly, it’s time for the initially very technical descent from the Karwendelhaus to the small Ahornboden. Out of habit, I start braking with two fingers, before convincing myself to take one finger off the levers. The braking performance is beyond reproach, but the real benefit is the improved handling that comes from having an extra finger on the handlebar. We already appreciated this feature on the road version, but it makes even more sense on a gravel bike. Rocks, potholes, branches… the more fingers you have on the handlebars, the more control you have over the bike.

With the 46 t sprocket, every climb loses its terror.
Well, almost every one.

Here the additional thumb switch on the top of the hoods also comes into play. With your index fingers on the brakes, too far away from the paddle shifter to change gears without moving your grip, the thumb takes over. Three fingers on the handlebar, one on the brake and the thumb on the shifter – the braking performance of RED XPLR AXS allows a whole new hand position on the handlebar. The light and not overly profiled rubber ensures you stay blister-free, even without gloves, while maintaining control on the descent. Speaking of control, the new clutch keeps the long derailleur cage on a short leash and prevents the chain from jumping excessively.

Learning a new way of thinking – the brakes have enough power to brake with one finger, from the hoods.

Conclusion

The new SRAM RED XPLR AXS is an exciting gravel groupset. The massive direct mount rear derailleur is precise, fast and easy to repair, while the 10-46 cassette offers a huge range and smooth modulation. Completely unexciting, however, are the brakes. Even with just one finger, they decelerate so confidently that it’s almost boring. The price, on the other hand, will get your pulse racing. The SRAM RED XPLR AXS is expensive, but it’s undeniably top of the range.

A little shade, a lot of light and a pretty penny – the SRAM RED XPLR AXS is really good, and really expensive.

Tops

  • 13-speed 10–46 cassette for steep climbs
  • direct mount-rear derailleur for maintenance-free shifting precision
  • new lever design for powerful braking

Flops

  • eye-wateringly expensive

For more information visit sram.com


Did you enjoy this article? If so, we would be stoked if you decide to support us with a monthly contribution. By becoming a supporter of GRAN FONDO, you will help secure a sustainable future for high-quality cycling journalism. Click here to learn more.

Words: Nils Hofmeister Photos: Nils Hofmeister, SRAM